There is a long history of creating composite wood panels and structural members from wood materials unsuitable for peeler logs or dimensional lumber.
Such composite wood panels include: hard board, flake board, strand board, oriented strand board, wafer board, particle board, etc. Each of these composite wood panels has its respective method(s) of manufacture, strength characteristics and potential uses.
Wood flakes, strands and wafers for composite wood panels are frequently crosscut, i.e. cut across the wood grain so the grain runs lengthwise through the flake, strand or wafer. Many machines for cutting wood into flakes, strands and wafers are known and described in the prior art. Examples include ring flakers, disk flakers and drum flakers. Wood flakes, strands and wafers made with those machines are suitable for making prior art composite wood panels, but the flakes, strands and wafers do not have a consistent thickness, length or width. To improve dimensional consistency, the use of screens and cyclone separators have been used. However, neither of these methods ensures a high degree of dimensional consistency.
There have also been attempts made to increase a flexural strength of composite wood panels. For example, U.S. Pat. No. 4,675,138 teaches a method of manufacturing a corrugated wafer board in a single stage process using a convertible platen that morphs from a flat to a corrugated configuration.
Structural members of composite wood material have also been invented and are described, for example, by U.S. Pat. No. 4,241,133, which uses wood flakes cut using a round wood flaker or a helical comminuting shear to create fingerlings flaked in a ring-type flaker.
Wood pulp slurries have likewise been used to manufacture corrugated cardboard and structural panels. Published U.S. Patent Application 2010/0078985A1 teaches a honeycomb-shaped structural panel formed from a plurality of generally sinusoidally shaped strips molded, from a wood pulp slurry.
In spite of a long history of development, composite wood panels are heavier, less flex resistant and more susceptible to moisture intrusion than plywood or solid wood. There therefore remains a need for a strong, low density composite wood panel with a corrugated core, and a method of manufacturing same.